Cooling length

L = total heated or cooled length of heat transfer path, ft w = weight rate of fluid flow per tube, Ib/hr p, = viscosity of fluid, lb/ (hr) (ft)... 

Vertical Tubes For the following cases Reynolds number < 2100 and is calculated by using V = Wf/kD. The Nusselt equation for the heat-transfer coefficient for condensate films may be written in the following ways (using liquid physical properties and where L is the cooled length and At is - ts) ... 

The stretching force is a direct consequence of the distance of polymer solidification (DPS) in both processes (i.e., FLH in film blowing processes or cooling length in ribbon extrusion). In this sense, controlling DPS offers the possibility to control the final properties of films and ribbons. Table 24.3 lists typical values of stretching force as function of FLH and DR for blown films of LDPE. 

In the same way. Figure 24.6 presents the stretching force (F) as a function of DR for different total cooling lengths (X). The stretching force increases with increasing... 

Figure 24.9 Mean failure energy for (a) 3% and (b) 9% PS in HOPE at different cooling lengths...

Solving (Equation 2.64) to find we can estimate the cooling length, under conditions of external heat removal, required for a sustainable temperature value in a reaction volume ... 

A quite easy method of controlling the cooling length is to change the reactor radius R as well as the linear flow rate of reactants V, however, this results in a markedly decreased output. In accordance with Equation 2.94, an mcrease of V from 1 to 10 m/s will lead to a 1.6 times increase of while a tenfold change of R will lead to a more than 15 times change of... 

Table 2.5 The dependence of cooling length zone (Tp = 0 on the number of tubes N and radius R in3L shell-and-tube turbulent reactor for the ethylene hydrochlorination process (AP = 322.5 kg/m, q = 552 kilojoules/ kg, k = 10 1/mol-s, y = 1 m/s, Tq = -10 and AT = 100 C) ...

Push one end of a length of 20 cm. of stout copper wire into a cork (this wUl serve as a holder) at the other end make two or three turns about a thin glass rod. Heat the coil in the outer mantle of a Bunsen dame until it ceases to impart any colour to the dame. Allow the wire to cool somewhat and, while still warm, dip the coil into a small portion of the substance to be tested and heat again in the non-luminous dame. If the compound contains a halogen element, a green or bluish-green dame will be observed (usually after the initial smoky dame has disappeared). Before using the wire for another compound, heat it until the material from the previous test has been destroyed and the dame is not coloured. 

The complete assembly for carrying out the catalytic decomposition of acids into ketones is shown in Fig. Ill, 72, 1. The main part of the apparatus consists of a device for dropping the acid at constant rate into a combustion tube containing the catalyst (manganous oxide deposited upon pumice) and heated electrically to about 350° the reaction products are condensed by a double surface condenser and coUected in a flask (which may be cooled in ice, if necessary) a glass bubbler at the end of the apparatus indicates the rate of decomposition (evolution of carbon dioxide). The furnace may be a commercial cylindrical furnace, about 70 cm. in length, but it is excellent practice, and certainly very much cheaper, to construct it from simple materials. 

Heating under reflux.—A water condenser of total length 25 cm, (cooling jacket 15 cm.) may be used. If the upper end is provided with a long side arm as in Fig. XII, 2, 9, refluxing may be followed by distillation without transferring the contents of the flask it may be necessary to surround part of the side arm with a short water condenser (compare... 

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